Wyniki wyszukiwania - BazTech

1

Energy accumulation in mechanical resonance and its use in drive systems of impact machines

Fiebig Wiesław, Wróbel Jakub

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 1

415--425

EN

An innovative method utilizing the phenomenon of mechanical resonance in machine drive systems of impact machines has been described. Energy accumulated in mechanical resonance is typically multiple times larger than the continuously supplied excitation energy. The amount of accumulated energy depends on the amplitude of vibration, mass and stiffness of system and present energy dissipation mechanisms. This form of energy can be extracted periodically each time after the amplitude of vibration reaches its maximum value. This effect could be implemented in drive systems of periodically operating machines, such as punching machines and presses. Significant reduction of energy demand in machines that use mechanical resonance in comparison with conventional machines was confirmed by means of simulations and experiments. Accumulation of the energy at mechanical resonance and its sequential extraction were presented together with a new pro-totype resonance punching press.

2

Mechanical resonance in high speed permanent magnet brushless dc motor

Hetmańczyk J., Krykowski K.

Prace Naukowe Politechniki Śląskiej. Elektryka

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2016

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z. 2

23--32

EN

The paper presents how to determine the ranges of rotational speeds for high-speed brushless DC motors (PM BLDC), in which the mechanical resonance caused by flexural and torsional vibrations occurs. In the comparative analysis real measurement data of the developed high-speed PM BLDC motors have been used. Presented results of a laboratory experiment confirmed the correctness of the method of calculation of resonance occurrence in PM BLDC motor.

PL

W artykule przedstawiono sposób wyznaczenia zakresów prędkości obrotowych dla wysokoobrotowych bezszczotkowych silników prądu stałego (PM BLDC), w których występuje rezonans mechanicznych drgań giętnych i skrętnych. W analizie porównawczej wykorzystano rzeczywiste dane opracowanych wysokoobrotowych silników PM BLDC. Przedstawiono wyniki eksperymentu laboratoryjnego potwierdzające poprawność sposobu obliczeń wstępowania rezonansów w silniku PM BLDC.

3

Selected problems of transmission wear of the Mi-24 helicopter

Gębura A., Zientalski K.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

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2015

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nr 37

25--44

EN

The hypothesis of mutual, destructive impact of the worn upper bearing of the WR-24 transmission on the Mi-24 helicopter's gearbox was stated. The Mi-24 is the only helicopter operated in Poland, in which the gearbox is mounted outside the main transmission – in the centre of the transmission shaft, between the main gearbox and the tail rotor. Damage to the gears in the gearbox of power generators is equivalent to termination of the tail rotor's drive. Such a termination immediately causes rotation of the body in the direction opposite to the direction of rotation of the main rotor. It is associated with the loss of lift and steering. It may lead to a disaster. Such an incident occurred in January 2011 in Afghanistan – both authors participated in its investigation. The authors, taking into account very good, almost legendary combat properties of the Mi-24, and their research of the specifics of wear and tear of the transmission elements, they think that, first, funds for development and implementation of the drive unit monitoring system should be made available specially for this helicopter. For this purpose, the authors propose to use the FAM-C method. It is characterised with significant ergonomics. Thank to this, multiple kinematic pairs can be observed simultaneously, and, therefore, the relationships between them as well.

4

Wpływ wymiarów wirnika na wybrane właściwości wysokoobrotowego bezszczotkowego silnika prądu stałego

Hetmańczyk J., Krykowski K., Skoć A.

Maszyny Elektryczne : zeszyty problemowe

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2014

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Nr 1(101)

43--48

PL

W artykule przeanalizowano wpływ relacji pomiędzy długością i średnicą wirnika na straty całkowite i sprawność wysokoobrotowego bezszczotkowego silnika prądu stałego (PM BLDC). Określono ograniczenia długości wirnika wynikające z możliwości pojawiania się drgań rezonansowych oraz zalecono sposób doboru relacji pomiędzy średnicą a długością wirnika. W rozważaniach wykorzystano dane prototypowych wysokoobrotowych silników PM BLDC, opracowanych w Katedrze Energoelektroniki, Napędu Elektrycznego i Robotyki Politechniki Śląskiej.

EN

Influence of the relation between length and diameter of the rotor on total losses and efficiency of high speed permanent brushless DC motor was analyzed in the paper. Limitations of rotor length resulting from the possibility of resonance vibrations appearance were determined and the way of selection of the relation between rotor length and diameter was recommended.The considerations were based on data of highspeed permanent brushless DC motor prototypes elabo rated in the department of Power Electronics, Electrical Drives and Robotics (KENER) The Silesian’s University of Technology.

5

Digital filter tuned according to spectral analysis of direct drive to reduce mechanical resonance effect

Łuczak D.

Computer Applications in Electrical Engineering

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2012

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Vol. 10

194--204

EN

Review of the filter structures and spectral analysis algorithms was done. Digital filters allow filtering the speed signal in control loop of direct drive with a mechanical resonance. The analogue filter equations were transformed into digital filters to enable tune them in real time. Spectral analysis with additional algorithm allows to determine the mechanical resonance frequency of multi-mass system. Determination of resonance frequencies allow for proper tune the digital filter. This paper presents selected algorithms of determine signal spectrum. In order to determine the mechanical resonance frequency from the whole spectrum, it is require to use an additional algorithm that was omitted from the consideration. Filters were tuned according to frequency characteristics of the object.